5G Massive MIMO
Challenges of massive MIMO in 5G
Massive MIMO is a core technology of the
5th generation mobile communication
Massive MIMO supports continuous
development of 5G network application
Multi-beam management and beamforming lay a
foundation for better coverage
5G SSB offers much better flexibility for broadcast channel
coverage than 4G
Evolution from horizontal multi-beam basic coverage to
full-scenario three-dimensional coverage
Efficient automatic optimization of 5G SSB
SU-MIMO and enhanced scenario-based algorithm enhance
user experience wherever and whenever needed
SU-MIMO helps realize the ultimate experience of a
Guaranteed user experience anytime and anywhere
Digital twin can help Massive MIMO realize
intelligent value evolution of physical networks
Summary and expectation
Table 1 Summary of features/challenges/key technical points at
each aspect of 5G network development and application
Figure 1 5G typical network coverage scenario
Figure 2 Comparison between 4G broadcast channel and 5G SSB
Figure 3 Full-scenario three-dimensional SSB coverage solution
Figure 4 SSB antenna parameters intelligent optimization flow
Figure 5 Mapping model of digital twin network and physical network
Table of contents
MU-MIMO SDMA pairing algorithm and QoS intelligent
scheduling help enhance system capacity and capability
MU-MIMO is the basis for multi-user and multi-layer
pairing optimization and enhancement of system capacity
QoS-based intelligent scheduling
One of the greatest things in our era is that 5G is helping realize the Intelligent Internet of Everything (IIoE),
bringing great changes to people’s lives, many vertical industries and the entire society with making the world a
better connected and digital one. Massive MIMO, as one of the core technologies of 5G, is key to meeting the high
performance requirements and new service requirements of this amazing new era.
Though Massive MIMO does offer great promises for highly capable 5G with wider bandwidth, more connections,
lower latency and better reliability, realizing its full potentials requires effective responses to the challenges of
network coverage, user experience, and network capability, which is relevant to all the mobile network operators
and system vendors.
After the Massive MIMO technology is introduced, the differentiation and flexibility of wireless network coverage
in three-dimensional space have been greatly improved. The radio wave propagation model, user behavior and
service distribution, beam management and beamforming are more complicated, flexible and difficult to measure.
The location of problems in wireless networks, the effectiveness of response solutions, and the effectiveness and
impacts of new functions become more complicated as the network scale increases. How to effectively predict, find,
and evaluate the optimal solution in advance before the complicated real network encounters problems?
While Massive MIMO enables 5G with much higher diversity and flexibility of network accessibility and capability in
a three-dimensional space, the complexity of the network raises the questions in identifying network issues, offering
effective solutions, and maximizing the benefits of the new technologies without paying too high a price. How
can we predict what network problems would happen under which circumstances, and come up with the optimal
solutions and evaluate them, before the problems really happen?
This white paper will address all these challenges with some analyses and suggestions.
Massive MIMO, a large-scale antenna technology, is a core 5G technology that can improve network coverage, user
experience and network capability.
While the traditional radio devices often have just two, four, or maximum eight TRX channels, the radio devices
powered by Massive MIMO technology can have 32 or 64 TRX channels, with up to 512 or even more antenna
elements, which can lead to substantially higher capacity gain than traditional equipment. Furthermore, while the
traditional devices focus more on coverage in horizontal dimension, Massive MIMO offers much better flexibility also
in vertical dimension. Massive MIMO can exploit to a great extent the resources in space dimension and enable the
users under the same base station to use the same time and frequency resources, which significantly enhances the
network capacity without denser base stations and wider frequency bandwidth.
The Massive MIMO technology was first introduced into mobile networks in Pre5G era. With deployments of 5G
around the world, it has now been widely adopted on a large scale.
Massive MIMO is a core technology of the 5th
generation mobile communication
Massive MIMO is a core technology of the 5th generation mobile communication
Challenges of Massive MIMO in 5G
Challenges of Massive MIMO in 5G network deployment
Massive MIMO technology can significantly improve the system capacity, but there are still many challenges to
be overcome while deploying the actual networks. These challenges are coupled mainly to three key aspects of
deploying 5G: network coverage, user experience and network capability.
The above three aspects will benefit greatly from the typical technical features and advantages of Massive MIMO, and
the corresponding technical difficulties will be solved at the same time.
Taking synchronization signal and PBCH block (SSB) configuration as an example, SSB determines the basic coverage
performance of the network. 4G broadcast channel is sent with a fixed wide beam, and its coverage does not change
in most cases. However, 5G SSB can be configured with up to 7 (2.5 ms frame structure) or 8 (5 ms frame structure)
beams according to frame structure. More SSB beams result in flexible configuration, i.e. multiple horizontal beams
can be configured, or combination of horizontal and vertical beams can be configured. Different beams can be
flexibly configured with different widths and heights, so that the 5G SSB beam configuration can support abundant
scenarios and accurately meet differential coverage requirements. However, the increase in flexibility also brings a
significant increases in configuration complexity. There are more than tens of thousands of combinations of antenna
parameters configuration for 5G SSB beams. Here arises a huge technical problem on how to quickly and accurately
find the configuration that is most suitable for the current scenario among tens of thousands of antenna parameters
, and efficiently match the configuration with the change of scenarios and user behavior modes.
Based on the quasi-orthogonal characteristics among multi-user channels, Massive MIMO can greatly improve the
network capacity through SDMA. Due to the complexity of wireless channel propagation, and the randomness
of user distribution and services, the design of a base station requires a well-performed algorithm for downlink
transmission and uplink receiving to obtain a stable multi-user SDMA gain and anti-interference performance. Under
the condition of a given number of antennas, the complexity of the Massive MIMO algorithm increases rapidly with the
increase of the number of users and the maximum number of MU-MIMO multiplexing layers, which becomes one of the
key technical difficulties affecting system capacity.
User experience optimization needs to compensate for the weakness in weak-�eld environments, thereby providing
a high-quality experience anytime and anywhere.
From a radio access network perspective, user experience is first strongly dependent on network coverage and mobility
performance. Generally speaking, the farther the user is away from the base station, the weaker the signal they receive, and
consequently the lower the data rate. Cell edge is often the weakest spot of the network in terms of both coverage and user
experience. Massive MIMO, with its ability to form more precise and energy-concentrated beams, can greatly enhance the signals
received at cell edge, reduce interference to neighboring cells and improve user experience.
Another typical case of poor user experience is when the users are moving really fast, which makes the basis of Massive MIMO’s good
performance – reliable channel state information and channel estimation – questionable. In medium- or high-speed mobility cases, the
radio channels between the terminal and the base station are in constant and fast change, wh